From the Wildlife Conservation Society’s “Rarest of the Rare” list of critically endangered species 2010.

vaquita (photo: National Geographic)

Vaquita–“little cow” in Spanish–is the smallest of the cetaceans. This tiny ocean porpoise, endemic only to the northern part of the Gulf of California known as the Sea of Cortez, and rarely seen in the wild, is the species that will most probably disappear in the next years with only 150 left in the world

The greatest threat to the remaining vaquita is being caught up in fishing gear, particularly gillnets. They are also killed by commercial shrimp trawlers.

Source: sciencedaily.com